Autonomous robot for a school project

I am new to working with Arduino, but for an independent school project I have decided to play around with it and build an autonomous robot. It should avoid obstacles and eventually take pictures when it reaches an obstacle, as well as take pictures on after a specific time frame. I am just confused as to where I should start and am seeking any advice/ programs/ words of wisdom. Anything helps!

I also built a robot this summer. I think you should start build mechanical parts and assemble the engines. Then you can connect the cables.

I'm sorry if there's some error (I'm Italian).